Pressure lubricated track tractor roller



3 Sheets-Sheet l July 5, 1955 w. c. CARROLL PRESSURE LUBRICATED TRACKTRACTOR ROLLER Fued sept. 25, 1951 July 5, 1955 w. c. CARROLL PRESSURELUBRICATED TRACK TRACTOR ROLLER 3 Sheets-Sheet 3 Filed Sept. 25, 1951United States Patent O PRESSURE LUBRICATED TRACK TRACTOR ROLLER WilliamCraig Carroll, Portland, Oreg.

Application September 25, 1951, Serial No. 248,238

4 Claims. (Cl. 30S-107) The present invention relates primarily to anovel design of track tractor roller for use with crawler type tractorsand similar equipment employing pressurized lubrication in a novelcombination. These track tractor rollers are particularly useful in anenvironment of grit, such as mud and dirt, to provide proper lubricationto all surfaces of the bearing and to exclude dirt from the contines ofthe track tractor roller.

The improvements embodied in this invention consist of a novelcombination of a cam actuated pump to circulate lubrication to thebearing surface, as Well as check means in the vicinity of the bearingsurface, to hold the pressure to a desired maximum. Included in thiscombination are further structural elements to reduce the pressure inthe vicinity of the seal on the shaft, in order that loss of lubricantwill not be excessive through this opening, particularly in View of thepressurized lubrication. This combination of track tractor rollers, withpressurized lubrication therefor, is useful even with lip type elastomerseals, which are angulated outward and allow for a slight extrusion oflubricant over the bearing unit in order to ow away particles of dirtwhich may become embedded beneath the lips of the seal.

This invention further relates to a novel design of track tractor rollerin which large lubricant capacity exists within the shell in order thatthe rollers of a tractor may be subjected to extreme conditions of usagein mud and dirt over long periods of service with slight lubricantextrusion past the seal and without undue wear or excessively frequentlubricant renewal.

This invention further relates to a pressurized track tractor roller inwhich lubricant is pressurized on the bearing surface but is relativelyunpressurized in the Vicinity of the lubricant seal on the shaft, inorder to avoid excessive extrusion of lubricant past the seal. Thisparticular type of track tractor roller is of the center thrust type,which is capable of withstanding heavy loads of a crawler type tractorwithout squashing out the lubricant between the shaft and the bearingwhile permitting side thrust from either side, particularly when thetractor is on a side hill. This pressurized track tractor roller isuseful either with single or double rail tracks, whichever may beemployed.

An object of this invention is to provide a pressurized track tractorroller with lubricant check valves surrounding the bearing surface and arelatively low pressure lubricant seal for said combination.

A further object of this invention is to provide a large lubricantstorage space within the connes of the shell of the track tractor rollerin order that there may be proper lubrication to all of the bearingsurface even though a major part of the lubricant has worked out of thetrack tractor roller.

A further object of this invention is to produce a track tractor rollerin which a cam actuated plunger pressurizes the lubricant in thevicinity of the bearing but connes it to that region in order that thebalance of the lubricant within the shell, and particularly in thevicinity of the JZ' Patented July 5, 1955 lubricant seals, is atrelatively low pressure in order to permit the successful operation ofthe track tractor roller over long periods of time without extrusion ofgreat quantities of lubricant.

A futher object of this invention is to produce a track tractor rolleremploying pressurized lubrication to the bearing surface of the roller,together with large lubricant storage capacity in the contines of theshell, while restricting the flow of the pressurized lubricant to theimmediate vicinity of the bearing, and providing bleeder channels fromthe vicinity of the seal to the lubricant storage space in order thatthe bulk of the lubricant, particularly in the vicinity of the seals,will be at relatively low pressure, whereas the lubricant in thevicinity of the bearing will be at high pressure.

To the accomplishment of the foregoing and related ends, said inventionthen consists of the means hereinafter fully described and pointed outin the claims; the following description setting forth in detail certainnovel features of construction and combination of parts which will bereadily understood by those skilled in the art to which the inventionappertains.

In the drawings, which illustrate one embodiment of the invention, Fig.l is a cross-sectional view of a pressurized track tractor roller,

Fig. 2 is a transverse cross-section of the roller along lines 2 2 ofFig. l showing the left bearing thrust surface,

Fig. 3 is a transverse cross-sectional View of the track tractor rolleralong the lines 3 3 of Fig. 1, looking to the left in Fig. l, showingthe construction of the lubricant pump,

Fig. 4 is a fragmentary cross-sectional View of Fig. l along the lines 44 of Fig. l, showing the construction of the lubricant passages to thebearing surface, and

Fig. 5 is a fragmentary detailed view in perspective of the double liplubricant seal preferably employed with this invention.

In this pressure lubricated track tractor roller Fig. l at 10 shows theouter shell which may be a single steel casting, possibly of high carbonmanganese alloy steel, which makes it capable of being subjected toextremely rough surface conditions. This cast shell has particularadvantage in that it permits part of the space within the outer castshell to be used as an annularly shaped reservoir, designated 1l and 12for the storage of lubricant. These reservoirs cause the outer thicknessof the shell to be of approximate constant thickness for greater ease incasting of the shell. The shell may be of the double iiange type, asshown here, on which there are a pair of outer anges designated 13 tothe right and 14 to the left, and similarly a pair of inner anges 15 onthe right and 16 on the left. These anged surfaces contact the endlesstrack chains of crawler type tractors, and through the medium of thetrack support the weight of the tractor.

In usual practice there may be as many as tive to seven pairs of thesetrack tractor rollers supporting the load of heavy crawler typetractors, weighing up to 30 tons or more. The load upon these tracktractor rollers is indeed enormous and the conditions of usage extreme.This particular track tractor roller has a large diameter axle 17,having a widened center portion 17a, which is used to absorb the sidethrust on the axle. On either side of the center thrust portions thereare a pair of bearings, 1S on the right and 19 on the left, which inturn are mounted on a pair of bearing carrier members, 20 on the rightand 21 on the left. These bearing carrier members have flanged portionsdesignated 22 on the right and 23 on the left, which extend over theexternal faces, 24 and 25, of the cast shell 10. Outwardly of thebearing carrier members there are seal housing members 26 and 27 mountedto the shell through openings in the bearing carrier members as well asthe cross-sectional view in Fig. l.

Vby Vmeans of Vcap screws 28.V Thus it may be seen that all of thesemembers, previously mentioned, rotate together as a unit including thebearing itself, around the shaft, which is stationary. The shaft in turnis secured to the side frame members of the track tractor roller bymeans of mounting blocks not shown. Within the cast shell there is anintegral cam portion 29, which is in the shape of a chord on thecircular portion of the shell and actuates the plunger type pump 30.

Thus it may be seen that on the interior side of the cast shell in thistrack tractor roller there are three lubricant reservoirs. 11 and 12 tothe right and left of the pump 30 and the central lubricant reservoirV3l. seen connected to these reservoirs. Pump provides lubrication toboth sides of the bearing surfacesV of this roller.

The exact manner in which the operation of this roller, and the partssubsequently to be described, can only be made clear is by anexamination of Figures 2, 3 and 4, For clarity, Fig. l will be brieflydescribed as wellas the manner in which the lubricant flows to allsurfaces of the bearing, and part of this description will' necessarilyhave to be repeated in connection with Figures 2, 3 and 4.

The remaining parts of this track tractor roller are most concerned withthe flow of lubrication to the various bearing surfaces. These can besupplied 'nest by tracing this ow of lubrication. Centrally of the axis17, and extending along a greater'portion of its length, is a lubricantchannel 32. On the end of this channel there is a lubricant fitting 33.Inwardly of the fitting is a widened portion 34, which has a spring 35,anda ball 36 mounted therein. The internal opening to the litting 37 isin contact with the ball 36, because of the pressure Vof the springagainst the end portion 33 of the enlarged diameter 34 within the bore.Thus it may be seen that should the fitting be accidentally removed orbroken off, lubricant Within the reservoir, under pressure, will causethe ball to seat and prevent a large loss of lubricant therethrough. Thecentral channel 32 of the axle has two radial openings 39 and 40, whichextend to enlarged portions 41 on the right and 42 on the left. Withinthese portions there is a seat 43 on the right and 44 on the left andballs 45 and 46, designed to contact the seat and seal the lubricantfrom-flowing back into the central channel 32. l

Centrally of the axle within the enlarged portion 17a there is alubricant pump 3i) with a plunger in an opening 47 of the axle, adaptedto contact the internal surface of reservoir 31 and be actuated by thecam portion 29 secured within this reservoir. The plunger` pump 30 has aroller 48 mounted on an axle 49, on one end of the pump. The roller isdesigned to contact the cam portion 29 and reciprocate within thecut-away portion 47 of the axle to force the lubricant to the'bearingsurface along channel 32 up the radial openings 39 and 4t) to thebearing surfaces 50 and 51. On the other end of the plunger pump thereis a spring 52 and a ball 53, which ball in turn seats against anopening in the axial passageway 54. In one end of the plunger pump thereis an opening to aid in the circulation of lubricant and to permitV theready mounting of the plunger pum within the cast shell for assembly. Y

A The operation of the lubricant system is to force the Vlubricantwithin the central channel 32 outwardly through transverse openings 39and 40, past seats 43 and 44, onto bearing surfaces 50 and 51, and theneventually into annular reservoirs 11 and 12. In order to force thelubricant in the manner described, check valve 53 closes as the ballseats into the lubricant passageway 54, so that the lubricant must go aspreviously described. On reverse stroke of the plunger pump 30,lubricant is drawn from the central reservoir 31, up through lubricantpassage 54, filling the suction space of the pump, whence it is forcedon the direct stroke into the central channel 32, to repeat These arethe large lubricant reservoirs `4 the pumping cycle which is virtually arecirculation of lubricant.

Once the lubricant is on the bearing surfaces 50 and 51 it will travelalong the bearing surfaces because the axle has a flattened portion 86on the top side of the shaft to provide improved distribution for thelubricant.

This flattened portion of the shaft does not extend the full length ofthe bearing and stops just before the end of the bearing at about 56 onthe right and 57 on the left. The lubricant will flow outwardly throughradially shaped lubricant passageways not shown on the center thrustsurfaces and into the central lubricant reservoir 31. cut-away portionsin the bearing carrier, which are designated 58 and 60 on the top andbottom right, and 59 and 61 on the top and bottom of the left side.These connect to the large lubricant reservoirs 1l and 12. From theoutward side into the lubricant reservoir thereY are bleeder channels 62on the right and 63 on the left top, and 64 and 650m the bottom Vrightand left respectively.

These carry the lubricant away from the vicinity of the seal back to thelow pressure area of the lubricant reservoirs 11 and 12.

Mounted within the bearing carrier members 2i) and 2l there are aplurality of check valves 66 and 68 on the top and bottom right, and 67and 69 on the top and bottom left. In all, there must be at least oneand perhaps as many as four of these check valves. They are designed toretain the pressure Von the bearing surface to at least 65 pounds persquare inch, and a ball and spring 70 and 71, respectively, of checkValve 68 are connected through'an opening 72 in the bearing face topermit the lubricant to flow through this opening past the ball andspring if the pressure is great enough to compress it, and out through asimilar opening 73. The remaining check valves are of similarconstruction.

By this construction of parts the lubricant on the bearing surface isheld at relatively high pressure and between strokes of the plunger pumplthe balls 45 and 46, which seat at 43 and 44 on the axial lubricantpassages 39 and 4t), prevent the lubricant from flowing away from thisarea, and accordingly reducing the pressure. Thus in each stroke, as theshell revolves, some quantity passes seats 43 and 44 onto the bearingsurfaces. Since these track tractor rollers rotate at from 150 to 350 ormore revolutions per minute and are subjected to such rough conditionsand heavy loads.fthey almost inevitably run hot and the need forlubrication is great. Thus this construction and combination of parts isbelieved to provide improved lubrication to the bearing surfaces, whileat the same time controlling the ow of lubricant over this surfacebecause of the check valves 66 through 69, as well as the restrictedopenings from the end of the bearing members.

On either end of v'the shaft, which is hardened, the clearance isreduced accordinglyV and there is no flat portion on the shaft. Thus itmay be seen that lubricant tiows by here. at a. reduced rate, and is notat the cornparable pressure of the bearing surfaces. If the lubricantshould occasionally be at high pressure withinthe vicinity of the seals,the bleeder channels 62 through 65 are designed to relieve thispressure, and to permit the lubricant to return to the annular lubricantreservoirs 11 and 12. Outwardly of these bleeder channels, the seals,which were previously mentioned, are located. These seals are designated74. on the right and on the left. VThey are of the double lip type, in,whichV elastomer rings are angulated outward, v/hich permit theextrusion of slight quantities of lubricant past the seal to flow awayparticles of dirt, which may become embedded between the seal and theshaft. In the immediate vicinity of the seals there is a portion cutaway from the housing, so that the seals are exposed to theexterior-conditions. Bythiswe mean that there is no protective housingor covering, in which dirt may be- It will be seen in addition thatthere are come lodged to force against the lips of the seals and wearthem into the shaft.

Fig. 2 shows a cross section of the track tractor roller along the lines2-2 of Fig. 1, that is, looking to the left in this view and in atransverse cross-section showing the cast shell of a double flangedroller having a circular ange 16 on the interior side and 14 on theexterior side. In addition there is a shaft 17 shown in cross-sectionhaving a bore therethrough 32 and a radial passage 4l) leading to awidened portion 42, having a seat therein 44 and a ball mounted on theseat. This is a lubricant passageway from the pump, not shown, throughthe axial bore 32 vertically through the radial passage 40 and outwardlyto the bearing surface 51. Since this View is taken outwardly of thewidened center portion of the ange 17a the pump does not show, but theilanged portion of the bearing 19 does at S1.

Between the shaft 17 and the bearing 19 there is a small amount ofclearance, which in this view is exaggerated because of the angulatedportion at the junction of the flanged portion of the bearing with thecylindrical portion. The bearing is secured to the bearing carrier 21 bymeans of dowels 84. At the outer surfaces of the bearing carrier thereare a plurality of passageways 59 and 61 longitudinally of the axle,which permit the flow of lubricant from the central reservoir outwardlyto the large lubricant reservoir 12. These passageways are designated 59on top and 61 on the bottom. This provides an even flow of lubricantfrom the pressurized bearing surfaces radially outward along the flangedbearing surface to the axial passageways 59 and 61 in the bearingcarrier and then to the reservoirs for subsequent re-use. in each ofthese passageways can be seen the bleeder channels 62 through 65, whichproject through the bearing carrier to the vicinity of the seal. Theseare shown at S5. In this figure four bleeder channels are shown, thoughin actual practice only two may be necessary.

Fig. 3 shows a cross-sectional view of the track tractor roller alonglines 3 3 of Fig. l looking to the left of this ligure, showing thedetailed mechanism of the cam actuated pump both in its operativeposition and in its inoperative position. In this view the shell 10 maybe seen with the flanges 14 and 16, as well as shaft 17, having acentral passageway 32 for lubricant. Within a cut-away portion 47, whichis transverse to the axle, there is a pump having a roller 48 mounted onthe outward side thereof in an axle 49. In the lower portion of thetransverse opening 47 there is a spring 52 and a ball 53 seated in thesmall opening S4, which f communicates with the central reservoir 31. Anintegral cam portion 29 partially lills the central reservoir and causesthe pump to force lubricant to the bearing surfaces on each revolutionof the track tractor roller. The position shown in dotted linesimmediately to the right of the pump is the same pump in an extendedposition as it passes the cam 29. For convenience the pump has beenshown as moving whereas in practice the roller and cam move relative tothe pump. Thus in this view roller 28a is mounted on an axle 49a and thecentral opening in the shaft is shown at 47a and is connected to thelubricant passage 54a. The axial lubricant passageways 59 and 61 permitthe lubricant to llow back and forth from the central reservoir 31 tothe side reservoirs 11 and 12, all within the shell member 10.

A further cross-sectional View of the shell is shown in Fig. 4, which isa view of the internal mechanism somewhat enlarged in the cross sectionshown in Fig. 2, and illustrates in this view the central passage 32 inthe axle 17, having a radial passageway to an en larged portion 42,forming a seat 44 for a ball 46. The lubricant passes up through thisopening to the bearing surface which has a partially flattened portion86. As previously described, this ilattened portion extends across thegreater portion of the cylindrical bearing sur- 6 face outwardly to theextreme edges thereof. In this manner lubricant is carried to allsurfaces of the bearing but is sometimes controlled and restricted inits ow from the bearing surfaces by reduced clearance at the end of thebearing surface. This clearance may be about .003 or .004 inch. Thegreater portion of the lubricant is expected to ow radially outward inthis clearance to the vicinity behind the seal and be carried by bleederchannels 63 and 65 to the lubricant reservoirs 11 and 12. A similarportion would travel along the axle to the iianged surfaces to thecentral lubricant reservoir. These bleeder channels, previouslymentioned, are shown in this View and designated 63 at the top. Othersare provided for at 90 relative to this bleeder channel.

Y This view further shows a cross-sectional view of the interior oflubricant reservoir 12, and projected into this cavity are tapped holesfor cap screws, generally designated S7. On the interior side of thelubricant seals there is a small annular chamber, which permits thelubricant to flow from any portion of the chamber to bleeder channels 63and 65, back to the lubricant reservoir.

lt is expected that the pressure on the lubricant behind the seals willnot be more than about 14 pounds per square inch, whereas the pressureon the bearing surface may be upwards of pounds. In this way thelubricant seals, which are of the double lip type about to be described,will not extrude excessive lubricant.

A preferred type of lubricant seal for this track tractor roller isshown in Fig. 5, where 9i) shows a metallic ring having a retainingilange 91 projected radially inwardly towards the shaft. Securely bondedto the retaining flange is a fibrous sealing ring 92 of elastomermaterial annular in shape but L-shaped in cross section, having acentral lip 93 which is inclined away from the retaining flange 91 andoutwardly of the track tractor roller. Thus it may be seen that thelubricant under pressure will extrude past the sealing ring 92 and itscentral lip 93. Outwardly of this lip on the lower part of the L thereis a grooved portion, behind which is mounted a coil spring 9d. At thelargest diameter of the L there is a projection 94, which lits into acomplementary groove between the retaining flange 91 and the metallicring 9i?. At the smaller diameter of the retaining ilange and on theinside surface thereof, there is a small cut-away portion 95, into whichthe heel of the L-shaped ring is designed to fit. This preventslubricant from flowing radially outward along the gap between theelastomer sealing ring 92 and the retaining flange 91 and provides atight contact therebetween. The central lip 93 has a conically shapedportion 96 directed away from the retaining flange 91, which will ilexunder pressure of the lubricant from within the track tractor roller.The above mentioned portion 96 contacts a shaft through lip 93 and isstiened by a cylindrical spring 98 against the grooved rear surface ofthe ring at 97.

In the novel position as used herein the sealing rings are directedangularly outwardly from the track tractor roller. Thus it may be seenthat they permit a slight extrusion of lubricant past the seal if thepressure of the retaining spring 98 is not excessive. Ordinarily about14 pounds of lubricant may be maintained within a track tractor rollerby this sealing arrangement.

In addition to this sealing ring there is a second ring, or washer, ofelastomer material spaced axially outward from sealing ring 92. Thissecond sealing ring 99 is supported by an annular shaped ring 100, whichis approximately parallel to the retaining ange 91. From the radiallyoutward side of ring 100, the largest diameter, and against the metallicring 90, there is an axial portion which extends into contact with theL-shaped sealing ring 92 at the top of the L and securely bonds thisportion into a cut-away portion 94. This second elastomer sealing ring99 is securely fastened to the and the shaft.

Y housing member. Thus no dirt or grit can force against the outersurfacek of this lip to force it into the Shaft and to wear groovestherein. Though I prefer to use this type of sealing means with thisdesign of track tractor roller it will readily be seen that other typesof seals may be used with this roller.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are, therefore, to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the` meaning andV rangeof equivalency of the claims are, therefore, 'mtended to be embracedtherein.

I claim:

l. ln a track tractor roller having an axle with a center thrustportion, a roller, flanged sleeve bearings having confronting surfacesagainst the center thrust portion; lubricant seals between the rollerand the axle; a lubricant pump within the axle and a lubricant systemwith passages to the bearing surface; restraining means on the bearingsurface to restrain the flow of lubricant; annularly shaped lubricantstorage spaces Within the roller with passages to saidk lubricant pumpand connecting passageways from Y the seal to said lubricant Vstoragespaces whereby lubricant. Si

is forced by the pumpv to the bearing surfaces and retained therein athigh pressures, and owsfoutwardly therefrom at reduced pressure to thesaid annularly shaped lubricant storage spaces, which are connected tothe Vlubricant pump, in order that the lubricant pressure behind theseals can be at relatively low pressure to permit the extrusion of aslight amount of lubrication past the seal.

2. In a track tractor roller having a roller, an axle with a centerthrust portion; bearing and bearing carrier Vmembers therefor withinsaid roller having confronting 8. cant upon the bearing surfaces; meanswithinV the axle for checking the back ow of lubricant from said bearingsurfaces and means within the said carrier members to relieve thepressure of lubricant in the immediate vicinity of the seals, to thelubricant reservoirs, wherebyY the lubricant pump forces lubricant tothe bearing surfaces at high pressure, where it is retained except forleakage past the ends of the bearings until the next strokerof the pump,

together with the means for relieving the pressure in the vicinity ofthe lubricant yseals by permitting flow of lubricant therefrom to therelatively low pressure reservoirs.

3. In a self-contained bearing and lubrication unit; an axle, .a roller,a bearing carrier and bearing secured thereto, confronting bearingsurfaces between said bearing and the axlejsaid roller having aplurality of spaced annular cavities interiorly of the roller; saidbearing car,

rier having a plurality of cavities therein connected -to the bearingsurfaces and supplementing said cavities in the roller to formAlubricant reservoirs for the unit; pumping means within the axleactuated by the roller for forcing lubricant to the bearing surfaces;restraining means in the bearing and bearing carrier and in the axle forretaining the lubricant on the bearing surfaces; lip

' type lubricant seals betweenthe roller and the axle;

bleeder channels from behind the sealsV to the lubricant reservoirswhereby the pump forces lubricant to the bearing surfaces at highpressure and restrains it therein, permitting the ow of lubricanttherefrom at lower pressures back to the lubricant pump with furtherpassageways from the vicinity of the seal to relieve any excess pressurewhich develops adjacent thereto to be rreturned to the lubricantreservoirs.

4. In a self-contained bearing and lubrication unit, a non-rotatingaxle, a roller, a bearing and bearing carrier secured thereto havingconfronting bearing surfaces between said bearing and the axle, meanswithin the roller for the storage of lubricant, connecting means in saidbearing carrier to said means within the roller for the storage oflubricant, pumping means within the axle actuated by the roller forforcing lubricant to the bearing surfaces, restraining means in thebearing and bearing carrier and in the axle for retaining the lubricanton the bearing surface, said restraining means in the axle comprising aball check valve in the upper portion of the nonrotating axle, alubricant seal between the roller and the axle, means for relieving thepressure adjacent the seal whereby pressure from the pump is forcedto'the bearing surface and restrained therein, and prevented .be-l

References Cited in the le of this patent UNITED STATES PATENTS BeretishJune 20, 1944 Carr Dec. 6, 1949

